Couplings have previously been know for use in connection with various medical treatments, e.g. the extracorporeal treatment of blood or other body fluids. The coupling of the present invention is primarily intended, however, to be used in conjunction with a method of treatment know as CAPD (Continuous Ambulatory Peritoneal Dialysis). In this method of treatment, a catheter is introduced into the patients' abdominal cavity, and projects as such or via a flexible tube through the abdominal wall. This flexible tube can then be connected by a coupling to a second flexible tube joined to a fluid bag. The coupling should thus consist of two coupling pieces or members, which are joined to the respective flexible tubes, or possibly directly to the bag itself and/or to the catheter. The first time such a coupling is used, there is normally no problem, since both coupling pieces can be supplied in a sterilized condition. After such first usage, however, when the fluid bag is to be replaced by a new one, at least one of the coupling pieces, i.e., the one connected to the abdominal catheter, may be contaminated by external impurities. It will be readily understood by those skilled in this art that this may give rise to various complications.
The couplings which are presently used for these purposes are primarily based on the principle that the patient should not be able to touch the inner parts of the coupling with his fingers. In this way, it should be possible to keep them sterile. However, a serious risk of contamination still exists if the outer components of the coupling are polluted or contaminated.